/*
 * Copyright 2021 Shulie Technology, Co.Ltd
 * Email: shulie@shulie.io
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package io.shulie.surge.data.runtime.disruptor;

/**
 * Coordination barrier for tracking the cursor for publishers and sequence of
 * dependent {@link EventProcessor}s for processing a data structure
 */
public interface SequenceBarrier
{
	/**
	 * Wait for the given sequence to be available for consumption.
	 *
	 * @param sequence to wait for
	 * @return the sequence up to which is available
	 * @throws AlertException if a status change has occurred for the Disruptor
	 * @throws InterruptedException if the thread needs awaking on a condition variable.
	 * @throws TimeoutException
	 */
	long waitFor(long sequence) throws AlertException, InterruptedException, TimeoutException;

	/**
	 * Get the current cursor value that can be read.
	 *
	 * @return value of the cursor for entries that have been published.
	 */
	long getCursor();

	/**
	 * The current alert status for the barrier.
	 *
	 * @return true if in alert otherwise false.
	 */
	boolean isAlerted();

	/**
	 * Alert the {@link EventProcessor}s of a status change and stay in this status until cleared.
	 */
	void alert();

	/**
	 * Clear the current alert status.
	 */
	void clearAlert();

	/**
	 * Check if an alert has been raised and throw an {@link AlertException} if it has.
	 *
	 * @throws AlertException if alert has been raised.
	 */
	void checkAlert() throws AlertException;
}
